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The Laboratory
in the News

Distant pollution sources affect cloud formations
A team of researchers, including Livermore computer scientist David Stevens, has determined a close tie between distant sources of pollution and the formation of clouds that influence global climate. The study focused on anvil cirrus clouds, an important but poorly understood element of Earth’s climate system.
In this study, researchers used data from a National Aeronautics and Space Administration (NASA) field experiment called CRYSTAL-FACE (Cirrus Regional Study of Tropical Anvils and Cirrus Layers—Florida Area Cirrus Experiment). The experiment obtained the first comprehensive measurements of aerosols and cloud particles throughout the atmospheric column during the evolution of multiple deep convective storm systems. Detailed cloud simulations that resolve the size distributions of aerosols and cloud particles were then made using the Livermore-developed DHARMA code. The researchers found that most anvil ice crystals form on midtropospheric aerosols—that is, on aerosols 6 to 10 kilometers above Earth’s surface. Scientists previously assumed that the aerosols needed for cloud formation are suspended closer to Earth’s surface.
This project was led by researchers from NASA’s Ames Research Center and included collaborators from the National Center for Atmospheric Research, University of North Dakota, Hampton University, Universidad Nacional Autónoma de Mexico, Stratton Park Engineering Company Inc., University of Denver, California Institute of Technology, and Center for Interdisciplinary Remotely-Piloted Aircraft Studies. The team’s findings were published in the April 30, 2004, issue of Science.
Contact: David Stevens (925) 422-7649 (dstevens@llnl.gov).

Gene-rich human chromosome-19 sequence completed
In the April 1, 2004, issue of Nature, a team of investigators, including researchers from Lawrence Livermore and Los Alamos national laboratories, described the completed sequencing of human chromosome 19, the most gene-rich of all the human chromosomes. The project is part of a long-term collaboration led by the Department of Energy’s (DOE’s) Joint Genome Institute (JGI) and the Human Genome Center at Stanford University and included researchers from the University of California at Santa Cruz; Children’s Hospital and Research Center in Oakland, California; the Howard Hughes Medical Institute at the University of Washington, Seattle; Case Western Reserve University; and the National Cancer Institute.
Although chromosome 19 represents only about 2 percent of the human genome, it has 55.8 million bases, or letters, of genetic code and features nearly 1,500 genes. Embedded in the completed sequence data are critical regulatory networks of genes tasked with controlling such functions as repairing DNA damage caused by exposure to radiation and to other environmental pollutants.
DOE originally selected chromosome 19 as a sequencing target to investigate the link between DNA damage from radiation exposure and human cancer. Livermore’s initial work, conducted in the mid-1990s, led to mapping many of chromosome 19’s DNA-repair genes. In 1999, DOE transferred the sequencing effort to JGI and the finishing effort to Stanford. Finishing is the painstaking process of ensuring that the information is completely contiguous and all ambiguities are resolved.
The estimated error rate of the completed chromosome-19 sequence is less than 1 in 100,000 base pairs, which far exceeds the 1 in 10,000 base-pair error rate established by the International Human Genome Sequencing Consortium. This version of the sequence is thus 500 times better than previous drafts in terms of contiguity and accuracy.
Contact: Susan Lucas (925) 296-5638 (lucas11@llnl.gov).

Counterintelligence effort receives excellent rating
Livermore’s Security Awareness for Employees (SAFE) Program earned an excellent rating from the Department of Energy’s (DOE’s) Office of Counterintelligence (OCI). It is the first overall excellent rating ever garnered by a DOE National Nuclear Security Administration counterintelligence office in such a thorough inspection.
The SAFE Program underwent an intensive audit by inspectors between March 22 and April 1, 2004. OCI inspectors rated SAFE in 12 areas, including management, operations, and liaison with other Laboratory organizations. The inspection report noted SAFE’s significant counterterrorism efforts during the past three years. According to the report, the program’s liaisons with other Laboratory organizations are particularly noteworthy, and its work with the Federal Bureau of Investigation is outstanding.
Contact: Terry Turchie (925) 422-6366 (turchie1@llnl.gov).

Thunder achieves record cluster efficiency
Lawrence Livermore’s newest supercomputer, called Thunder, debuted as the world’s second fastest supercomputer according to the Top500 list released in June 2004. In benchmark testing, Thunder achieved a sustained performance of 19.94 trillion operations per second (teraops). Its theoretical peak speed is rated at 23 teraops.
Thunder is a Linux cluster that runs an open source software environment called CHAOS (Clustered High Availability Operating System), which was developed by the Laboratory. The cluster has 1,024 nodes, each with four Itanium 2 processors that offer processing speeds up to 1.4 gigahertz. In tests, Thunder achieved a record cluster efficiency of 86.9 percent, an important measurement in cluster scalability. The complete Top500 list is available at www.top500.org.
Contact: Mark Seager (925) 423-3141 (seager@llnl.gov).



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UCRL-52000-04-7/8 | July 12, 2004